PORTLAND, Ore.— Two members of Oregon’s very small wolf population were killed this weekend by U.S.D.A. Wildlife Services with approval from the Oregon Department of Fish and Wildlife.

The pair of wolves, who had established residence in the Eagle Cap Wilderness in eastern Oregon, were one of only three pairs of wolves in the state.

“It saddens us that with so few wolves in the state, we lost these two animals,” said Noah Greenwald, endangered species program director at the Center for Biological Diversity.

Although the wolves killed livestock in April and May, efforts by the Oregon Department of Fish and Wildlife to haze the wolves away from ranches and fencing by livestock owners had succeeded in keeping the wolves from depredating any livestock for more than three months.

“With wolves struggling to come back in Oregon, efforts to keep these two wolves away from livestock should have been tried for longer,” said Greenwald.

The Center for Biological Diversity has sued the U.S. Fish and Wildlife Service for taking wolves off of the federal endangered species list in the northern Rocky Mountains, including eastern Oregon and Washington.

“We had hoped to gain an injunction in time to restore federal protections to wolves, including the two that were killed,” said Greenwald. “It was a race against time, and these wolves lost.”

Without federal protection, both Idaho and Montana have opened hunting seasons for wolves with Idaho planning to reduce the state’s population by as much as a third. This could make it far less likely that wolves continue to colonize suitable habitat in Oregon.

“The killing of these two animals clearly shows that wolves remain highly threatened and need the protection of the Endangered Species Act if they are to recover in Oregon and elsewhere,” said Greenwald. “Wolves are an incredibly important part of our environment, with research in Yellowstone National Park showing that reintroduction of wolves keeps elk and other ungulates on the move, leading to increased streamside vegetation, which in turn benefits numerous other species, such as beavers and songbirds.”